Note 13 - Warrants

9 Months Ended

Sep. 30, 2017

Notes to Financial Statements

Warrants [Text Block]

Note 1 3 . Warrants

Common Stock Warrants

Following is a summary of all warrant activity for the

nine

months ended

September 30, 2017: 

Warrants	Number of Warrants Issued			Weighted Average Exercise Price
Warrants outstanding at December 31, 2016		1,487,958		$	9.39
Warrants issued during the nine months ended September 30, 2017 (see Note 10)		6,679,378			3.08
Warrants exercised during the nine months ended September 30, 2017 (see Note 10)		(2,638,702	)		1.92
Warrants outstanding at September 30, 2017		5,528,634		$	5.33
Aggregate intrinsic value of outstanding warrants at September 30, 2017	─
Weighted average remaining contractual terms at September 30, 2017 (in years)		3.16